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The latest from the MySQL community

Ideas, releases, practical guides, and perspectives from the people building with MySQL.

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MySQL Replication and GTID-based failover - A Deep Dive into Errant Transactions

For years, MySQL replication used to be based on binary log events - all a slave knew was the exact event and the exact position it just read from the master. Any single transaction from a master may have ended in different binary logs, and in different positions in these logs. It was a simple solution that came with limitations - more complex topology changes could require an admin to stop replication on the hosts involved. Or these changes could cause some other issues, e.g., a slave couldn’t be moved down the replication chain without time-consuming rebuild process (we couldn’t easily change replication from A -> B -> C to A -> C -> B without stopping replication on both B and C). We’ve all had to work around these limitations while dreaming about a global transaction identifier.

GTID was introduced along with MySQL 5.6, and brought along some major changes in the way MySQL operates. First of all, every transaction has …

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Video: MySQL Replication & ClusterControl Product Demonstration

The video below details the features and functions that are available in ClusterControl for MySQL Replication.  Included in the video are…

  • How to Deploy Master-Slave Replication
  • How to Deploy Multi-Master Replication
  • MySQL Replication overview including metrics
  • Individual Node overview & management
  • Backup management from Slaves or Masters
  • Adding Nodes
  • Adding Load Balancers

ClusterControl Single Console for Your Entire Database Infrastructure Find out what else is new in ClusterControl Install ClusterControl for FREE ClusterControl for MySQL Replication

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MySQL Group Replication: who is the primary master ??

As you know, MySQL Group Replication runs by default in single primary mode.

mysql2 mysql> show global variables like 'group_replication_single_primary_mode';
+---------------------------------------+-------+
| Variable_name                         | Value |
+---------------------------------------+-------+
| group_replication_single_primary_mode | ON    |
+---------------------------------------+-------+

But how can we easily find which member of the group is the Primary-Master ?

Of course you could check which one is not in read_only:

mysql2 mysql> select @@read_only;
+-------------+
| @@read_only |
+-------------+
|           1 |
+-------------+

But then you need to perform this on all the nodes one by one until you find the right one.

The primary …

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The Puzzling Performance of the Samsung 960 Pro

In this blog post, I’ll take a look at the performance of the Samsung 960 Pro SSD NVME.

First, I know the Samsung 960 Pro is a consumer SSD NVME drive, not intended for sustained data center workloads. But the AnandTech review looked good enough that I decided to take it for a test spin to see if it would work well with MySQL benchmarks.

Before that, I decided to do a simple sysbench file IO test to see how the drives handled sustained workloads, and if it would start acting up.

My expectation for a consumer SSD drive is that its write consistency will suffer. Many of those drives can sustain high bursts for short periods of time but have to slow down to keep up with write leveling (and other …

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MySQL Connector/Python 2.2.3 m4 Development Release has been released

MySQL Connector/Python 2.2.3 M4 is the fourth development release of the MySQL Connector Python 2.2 series. This series adds support for the new X DevAPI. The X DevAPI enables application developers to write code that combines the strengths of the relational and document models using a modern, NoSQL-like syntax that does not assume previous experience writing traditional SQL.

To learn more about how to write applications using the X DevAPI, see http://dev.mysql.com/doc/x-devapi-userguide/en/. For more information about how the X DevAPI is implemented in MySQL Connector/Python, and its usage, see http://dev.mysql.com/doc/dev/connector-python.

Please note that the X DevAPI requires MySQL Server version 5.7.12 or higher with the X Plugin enabled. For general …

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Percona Server for MySQL 5.5.54-38.7 is Now Available

Percona announces the release of Percona Server for MySQL 5.5.54-38.7 on March 22, 2017. Based on MySQL 5.5.54, including all the bug fixes in it, Percona Server for MySQL 5.5.54-38.7 is now the current stable release in the 5.5 series.

Percona Server for MySQL is open-source and free. You can find release details in the 5.5.54-38.7 milestone on Launchpad. Downloads are available here and from the Percona Software Repositories.

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LOAD DATA INFILE into a BIT field

https://dev.mysql.com/doc/en/load-data.html

BIT values cannot be loaded using binary notation (for example, b’011010′).

$ cat test.txt

b'101010'
0b111000

-----

CREATE TABLE loadTest (b BIT(6));

LOAD DATA LOCAL INFILE 'test.txt' INTO TABLE loadTest;

/*--------+------+---------------------------------------+
| Level   | Code | Message                               |
+---------+------+---------------------------------------+
| Warning | 1406 | Data too long for column 'b' at row 1 |
| Warning | 1406 | Data too long for column 'b' at row 2 |
+---------+------+--------------------------------------*/

-- Note the wrong values:

SELECT BIN(b) FROM loadTest;
/*-------+
| BIN(b) |
+--------+
| 111111 |
| 111111 |
+-------*/

TRUNCATE loadTest;

LOAD DATA LOCAL INFILE 'test.txt' INTO TABLE loadTest (@b) 
  SET b = CAST(CONV(TRIM('''' FROM SUBSTRING_INDEX(@b, 'b', -1)), 2, 10) AS …
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MariaDB Galera Cluster 10.0.30 and Connector/J 1.5.9 now available

The MariaDB project is pleased to announce the immediate availability of MariaDB Galera Cluster 10.0.30 and MariaDB Connector/J 1.5.9. Both of these are stable (GA) releases. See the release notes and changelogs for details. Download MariaDB Galera Cluster 10.0.30 Release Notes Changelog What is MariaDB Galera Cluster? MariaDB APT and YUM Repository Configuration Generator Download […]

The post MariaDB Galera Cluster 10.0.30 and Connector/J 1.5.9 now available appeared first on MariaDB.org.

Multi-Source Replication

A basic MySQL or MariaDB replication arrangement uses a simple method to perform replication. Any changes to schema or data on the master are recorded in its binary log. The slave regularly asks the master for any new entries to its binary log, based on position numbers in that log. The slave will record any new entries the master sends it in a relay log and then execute them on its copy of the databases. This system works well with a straightforward master-slave configuration, when there is only one master and one or more slaves.

With recent releases of MySQL and MariaDB, a slave can have multiple sources for replication. This may seem absurd at first until you consider one of the inherent points of replication: load balancing. Slaves are typically used for Read load balancing—to spread traffic related to SELECT statements among several servers. With multi-source replication, Writes can also be load balanced. For a large organization with …

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How to setup three nodes MariaDB Galera Cluster on Single server with MySQL sandbox

For the production environment, it’s recommended that we should use separate server for each Galera Cluster node but sometimes, for the testing purpose we have to setup it on one server with different ports. Here are the steps for how to do that with CentOS 6.8, MariaDB Galera Cluster 10.1.21 and MySQL Sandbox

  • Download MariaDB 10.1.21 from this location

https://downloads.mariadb.org/mariadb/10.1.21/

  • If you want to use sst method = xtrabackup then install it with yum repo    

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